Device for automatically switching off a telephonograph



1950 M. HANDSCHIN 2,519,567

DEVICE FOR AUTOMATIC SWITCHING OFF TELEPHONOGRAPHS Filed Feb. 27, 1948 OUTPUT AMP. INPUT I INPUI OUTPUT F/FR Patented Aug. 22, 1950 DEVICE FOR AUTOMATICALLY SWITCHING OFF .A TELEPHONOGRAPH Max Handschin, Kusnacht, Switzerland, assignor to Daphne Investment Trust, Vaduz, Liechtenstein Application February 27, 1948, Serial No. 11,816 In Switzerland July 30, 1947 4 Claims. 1

The present invention relates to a'device in a telephonograph for switching it off after reproduction has been performed, and to the method for operating the same.

Such devices have become known with sound recording instruments, particularly teiephonographs, in which mechanical friction clutches and the like-are provided. Although these mechanical components are being made with high accuracy, they have frequently given rise to disturbances. According to the invention this disadvantage is overcome thereby that the switching-off is effected exclusively by the electric means, for instance by a relay which remains energized only as long as the message is reproduced and becomes deenergized to switch off the telephonograph at the end of the reproduced message.

The switching-off can for example be effected in such a manner that at the amplifier output the recorded frequencies are checked by means of a delayed-action relay. Such a device is cheaper in manufacture than the known arrangement with friction clutch, and is operated moreover more reliably.

A preferred embodiment of a device according to the invention is schematically represented in the accompanying drawing.

It is to be understood in the following that the positive leads are connected with the positive and grounded terminal of a battery, while the negative leads are connected to the negative terminal of the battery.

It be assumed that the sound carrier TT'I and with it the wire drum DT has run in a known manner into the starting position, so that upon energizing the electric clutch winding K6, the subscriber TI will be able to hear at once the recorded message.

In order to energize the clutch winding K6 the key JAIS is depressed for a short while so that, the relay HI I is energised from the following circuit:

(1) Earth, key JAk9, relay HI I, battery. The relay HI I, energizes on the one hand, the relay NI2, which puts the motor MI3 on the voltage of the mains NEI4 through its contact I5. The relay NIZ is energized by the circuit:

(2) Earth, contact I6, relay NI2, battery. The motor is energized by the circuit:

(3) Mains NeI I, contact I5, motor MI3, mains NeM.

Moreover the electromagnetic clutch K6 is energised by the circuit:

2 t (4) Earth, contact I8, clutch winding K6, batery.

Now the wire drum DT5, and therewith the sound record TT'I, are put into action in a known manner in the direction of the arrow. Now the subscriber TI will hear the message recorded on the sound record TTI by means of the pick-up S4, amplifier WV3 and coupling transformer U2. Parallel to the transformer U2 there may be for example arranged amplifier GRS and at the output thereof a relay J In which is now energized by the electric impulses or frequency signals which are discharged by the sound record.

It results the circuit:

(5') Subscriber TI, transformer U2, amplifier WV3 pick-up S4 and back to amplifier WV3, transformer U2, subscriber TI and parallel to the transformer U2, amplifier GR8, relay J I 0 and back to the amplifier GR8 and transformer U2.

The relay J II! can be one which for example drops off with delayed action in order to bridge short interruptions in the reproduced message. For this purpose a condenser K09 is provided. The contact 20 of the relay J II! will now take over the holding of relay HI I. Circuit (1) becomes inoperative and it results circuit:

(6) Earth, contact 20, contact I'I, holding coil of relay HI I, battery.

The relay HII and with it all talking circuits are now held so long until the relay J I0 is de-energized i. e. only as long as recordings are on the sound record TTTI and no further impulses of speech flow over the pick-up S4.

When the message has been reproduced and there are no longer any recordings on the sound record TT'I, the relay J 11: becomes (la-energized and therewith all other circuits too. The telephonographic apparatus is thereby switched ofi automatically.

What I claim as my invention and desire to secure by Letters Patent, is:

1. In a telephonograph, a sound record driven by an electric motor, an electric clutch drivingly connecting, when energized, said electric motor with said sound record, a subscriber telephone circuit, means connecting thereto a pick-up for reproducing the message recorded on said sound record, a relay provided with an operating coil and a holding coil, means including a manually operable switch in the circuit of said operating coil of said relay for controlling the operation of said electric motor to close the circuit of the latter when said switch is momentarily closed, said relay having contact means, closing at the same time the motor is energized, the circuit of said electric clutch to energize the latter, means including a second relay for closing, when energized, the circuit of said holding coil to maintain said electric motor and said electric clutch energized when said switch opens, said second relay being energized by the current impulses produced by the. message reproduced by said sound record and fed into said subscribers telephone circuit, said second relay being de-energized at the end of the reproduced message, owing to lack of current impulses, whereby the circuit of said holding coil is opened and as a result of which said electric motor and said electric clutch become deenergized.

2. In a telephonograph, a sound record driven by an electric motor, an electric clutch drivingly connecting, when energized, said electric motor with said sound record, a subscriber telephone circuit, means connecting thereto a pick-up for reproducing the message recorded on said sound record, a relay provided with an operating coil and a holding coil, means including a manually operable switch in the circuit of said operating coil of said relay for controlling the operation of said electric motor to close the circuit of the latter when said switch is momentarily closed, said relay having contact meansclosing, at the same time the motor is energized, the circuit of said electric clutch to energize the latter, means including a second relay for closing, when energized, the circuit of said holding coil to maintain said electric motor and said electric clutch energized when said switch opens, a coupling transformer having two coils, means connecting one of said coils to said subscriber telephone circuit and the other to the output of an amplifier,

rent impulses produced by said reproduced message at the output terminals of said first men-' tioned amplifiensaid holding .coil being deenergized at the end of the reproduced message when said second relay becomesdeenergized asa result of lack of current impulses to be amplified, so that said'electric motor and electric clutch will also become deenergized.

3. In a t'elep-honograph, a sound record driven by an electric motor, an electric clutch drivingly connecting, when energized, said electric motor with said sound record, a subscriber telephone circuit, means connecting thereto a pick-up for 4 reproducing the message recorded on said sound record, a relay provided with an operating coil and a holding coil, means including a manually operable switch in the circuit of said operating coil of said relay for controlling the operation of said electric motor to close the circuit of the latter when said. switch is momentarily closed, said relay having contact means, closing at the same time the motor is energized, the circuit of said electric clutch to energize the latter, means including a second relay for closing, when energized, the circuit of said holding coil to maintain said electric motor and said electric clutch energized when said switch opens, a coupling transformer having two coils, means connecting one of said coils to said subscriber telephone circuit and the other to the output of an amplifier, means connecting the input of said amplifier to said pick-up, a second amplifier, means connecting the input terminals second amplifier to the output terminals of the said first amplifier, means connecting the output of said second amplifier to said second relay, means including a condenser shunted across said second relay to cause a delay in its action upon deenergisation, said second relay being energized by amplified current impulses produced by said reproduced message at the output terminals of said first mentioned amplifier, and said holding coil being deenergized at the end of the reproduced message when said second relay becomes deenergized as a result of lack 'the circuit of the operating coil of the first mentioned relay isclosed, said third relay, when energized, closing the circuit of said electric motor and will become deenergized when the circuit of the-holding coil of said second relay is opened.

MAX HANDSCHIN.

REFERENCES CITED 7 The following references are of'record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,726,947 Chauvean Sept. 3, 1929 2,005,788 Keiser June 25, 1935 2,006,455 Hickman July 2, 1935 2,221,333 Rowe Nov, 19, 1940 

